Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Please check your email for login details.
MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping

The 15 que asking me the velocity at 4s If we differentiate x we get velocity as 61 m/s but when we but value of t as 4 in eq of x we get 134 m and by further dividing it by 4 we get velocity as 33.5 m/s ....why there is a difference....plz help me

The 15 que asking me the velocity at 4s
If we differentiate x we get velocity as 61 m/s but when we but value of t as 4 in eq of x we get 134 m and by further dividing it by 4 we get velocity as 33.5 m/s ....why there is a difference....plz help me

Question Image
Grade:11

1 Answers

Tanishq Gupta
31 Points
3 months ago
Hello Preet,
The velocity that you have calculated by differenciating ‘x’ with respect to time is absolutely correct that is 61 m/s.
Now as mentioned in the question the particle is in uniform acceleration motion so therefore in the condition of acceleration motion we cannot apply the formula ‘velocity = displacement / time’ for that the velocity must be constant.
Instead in the condition of acceleration motion we have to apply the equation of motion.
Verification : x=2+5t+7t2
initial velocity (u) = 5 m/s (at t=0)
acceleration (at t=4) = 14 m/s2
by 1st equation of  motion : v=u+at
v=5+14(4)
v=61 m/s
Hence Proved.
Hope you find it useful.

Think You Can Provide A Better Answer ?

Provide a better Answer & Earn Cool Goodies See our forum point policy

ASK QUESTION

Get your questions answered by the expert for free